A team of young doctors embarks on a humanitarian mission to the Amazon rainforest, full of enthusiasm to help those in need, but each of them with their own agenda. However, not everyone reacts kindly to their arrival, and their visit awakens an ancient predator: the Boiúna. This mythical creature, which hunts both on land and in water, returns to defend its territory. In the midst of the dense jungle, a merciless struggle for survival ensues, in which the boundaries between hunter and prey, hero and villain, become increasingly blurred.